van der Werf Tjip S, Zijlstra Jan G
Intensive and Respiratory Care Unit, Department of Internal Medicine, Groningen University Medical Center, P.O. Box 30001, 9700 RB, Groningen, The Netherlands.
Intensive Care Med. 2004 Feb;30(2):183-184. doi: 10.1007/s00134-003-2083-6. Epub 2003 Dec 19.